Alternative to plywood floor

[bwillieb]

................multi laminate plywood (8 or 9 ply construction grade) is cheap at Home Depot.........cut your floor........brush on three coats of 'West Systems' Epoxy,......making sure to do the end grain and the grain inside any holes.......Google... Gougeon Brothers or West Systems,..for the trick way to attach your floor.......check your stringers closely for any signs of rot...........West Systems has been the salvation of wood problems in big boats for years.........If you know someone with port supply discount at 'West Marine' stores........your material cost will be greatly reduced..........Epoxy sticks to polyester resin(fiberglass)but not visa/ versa.......sounds like composites are the wave of the future?............

[sorry dog]

I will back up this post. Leaving the bottom of the wood open is the only way to go but that's only half the job. The other half is keeping the moisture out of the sub-floor and that means taking the foam out. Don't re-foam. People put pool noodles and all kinds of crap in there but that stuff just traps moisture and rots the wood.
How long can you expect a piece of plywood to last when it's got a wet sponge touching it?
I heard that PVC is the way to go for extra flotation material that lightens the boat.
BTW - I always take Ducky's advice. He makes some of the best drain plug designs in the world.

[martan]

I don't think resins will stick to PVC board. It's also exspensive and when I tried some I didn't think it was all that light.
www.bowkersfiberglass.com

[axkiker]

Why not go with a marine grade playwood. The stuff is guaranteed to not rot for like 30 years even in the water. Might be a little heavier but we are not talking about a crazy amount of weight on a 21 foot boat. Maybe an extra 25 lbs .

[Towndrunk]

Just take the plywood out and turn it over. Be sure to oil the rotted side with penz 10w30. Should be good for another 20 years.

[Kurtis500]

Depends on what you want to spend. You can get a good 3/4 inch aramid core and glass it on both sides. Closed cell core is what you would want. It may be a little tricky if you've never done it. Most of the time this kind of construction is vacuume bagged, but you can hand lay if you do it right. Most floor panels in aircraft are constructed with aramid cores and thermoplastics/thermosets. Or, for cheaper and easier, just glass over your plywood.

[Kurtis500]

I just recieve some samples from coosa composites. Has anyone ever used this stuff before? The adhesion is excellent and it seems to be a bit lighter than wood. I am looking into using this for upholstery such as in an engine hatch or seat boxes. It would just be so much easier than having to glass over everything and glue doesn't stick good to treated plywood. I am waiting to see how much a sheet of this stuff costs. I am hoping its cheaper than plastic board.
www.bowkersfiberglass.com
Yes I have used products from them. What product do you have? If its a coring material it wont be cheaper than a plastic sheet.